xash3d-fwgs-RPi
Half-Life Engine Port for Pi4
with the help from Cesarpuig over from the RetroPie fourms here is a updated install script for the Halflife, Blue shift and Opposing Force
wget https://raw.githubusercontent.com/Exarkuniv/xash3d-fwgs-RPi/Master/xash3d-fwgs.sh -P $HOME/RetroPie-Setup/scriptmodules/ports/